Zeolite ITQ-10

ABSTRACT

The present invention refers to a microporous rystalline material of zeolitic nature named ITQ-10, to the process of its preparation and to the use of ITQ-10 in processes of separation and transformation of organic compounds.  
     In calcinated and anhydrous state, the composition of the material ITO-10 corresponds to the empirical formula  
     x(M 1 / n XO 2 ):yYO 2 :SiO 2    
     wherein x has a value lower than 0.1 whereby it may be equal to zero; y has a value lower than 0.1 and may as well be equal to zero; M is H +  or an inorganic cation of a charge +n; X is a chemical element with oxidation state +3 (as for example Al, Ga, B, Cr) and Y is a chemical element with oxidation state +4 (as for example Ti, Ge, V). When x=0 and y=0, the ITQ-10 material may be described as a new polymorphous form of silica of microporous character. The zeolitic material of this invention is also characterized by its characteristic X-ray diffraction pattern and its microporous properties.  
     The preparation process is characterized by the use of one or several organic additives in a reaction mixture which is made to crystallize by means of heating.

TECHNICAL FIELD

[0001] Crystalline microporous materials.

BACKGROUND

[0002] Zeolites are crystalline microporous materials of varyingcompositions, characterized by a crystalline network of TO₄ tetrahedrons(wherein T represents atoms in a formal oxidation state of +3 or +4 asfor example Si, Ti, Al, Ge, B, Ga, . . . ) which share all theirvertices, giving rise to a tridimensional structure containing channelsand/or cavities of molecular dimensions. When some of the T atomspresent an oxidation state lower than +4, the thus formed crystallinenetwork presents negative charges that are compensated by the presenceof organic or inorganic cations in the channels or cavities. In saidchannels, there may also be housed organic molecules and H₂O for whichreason, in a general manner, the chemical composition of zeolites may berepresented by the following empirical formula:

x(M₁/_(n)XO₂):yYO₂:zR:z wH₂O

[0003] wherein M is one or several organic or inorganic cations ofcharge +n; X is one or several trivalent elements; Y is one or severaltetravalent elements, generally Si; R is one or several organicsubstances. Although the nature of M, X, Y and R and the values of x, y,2 and w may, in general, be varied by means of postsynthesis treatments,the chemical composition of a zeolite (as synthesized or after itscalcination) has a characteristic range for each zeolite and for themethod by which it has been obtained On the other hand, a zeolite isfurther characterized by it crystalline structure which defines a systemof channels and cavities that gives rise to a specific X-ray diffractionpattern. In this manner, zeolites differ in respect of each other by itsrange of chemical composition plus their X-ray diffraction pattern. Bothcharacteristics (crystalline structure and chemical composition) furtherdetermine the physical-chemical properties of each zeolite and itsapplicability in different industrial processes.

DESCRIPTION OF THE INVENTION

[0004] The present invention refers to a crystalline microporousmaterial of zeolitic nature, named ITQ-10, to a method for obtaining itand to the uses thereof.

[0005] Such a material is characterized by its chemical composition andby its X-ray diffraction pattern. In its anhydrous and calcinared form,the composition of ITQ-10 can be represented by means of the followingempirical formula

x(M₁/_(n)XO₂):yYO₂:SiO₂

[0006] wherein x has a value lower than 0.1 whereby it may be equal tozero; y has a value lower than 0.1 and may as well be equal to zero; Mis H⁺ or an inorganic cation of a charge +n; X is a chemical elementwith oxidation state +3 (as for example Al, Ga, B, Cr) and Y is achemical element with oxidation state +4 (as for example Ti, Ge, V).When x=0 and y=0, the material may be described as a new polymorphousform of silica (SiO₂) being characterized by its microporous character.In a preferred form of the present invention, in calcinated andanhydrous state, ITQ-10 has the composition

x(HXO₂):SiO₂

[0007] wherein X is a trivalent element and x has a value lower than 0.1and may be equal to zero, in which case the material may be described bymeans of the formula SiO₂. However, depending on the method of synthesisand on its calcination or subsequent treatments, the presence of defectsin the crystalline network manifesting themselves in the presence ofSi-OH groups (silanols) is possible. These defects have not beenincluded in the previous empiric formulas. In a preferred form of theinvention ITQ-10 only has a very low concentration of this kind ofdefects (silanol concentration lower than 15% in respect of the wholeamount of Si atoms, preferably lower than 6%, measured by 29Si nuclearmagnetic resonance spectroscopy in magic angle).

[0008] The X-ray diffraction pattern of ITQ-10 as synthesized by thepowder method using a set divergence split is characterized by thefollowing values of interplanar spacings (d) and relative intensities(I/I₀): TABLE 1 d(Å) I/I_(o)(%) 12.26 20 11.58 25 9.14 10 5.35 5 4.65 104.35 20 4.16 20 4.01 40 3.91 100 3.78 25 3.66 15 3.51 5 3.39 10 3.24 153.10 20 2.94 10 2.82 10 2.62 5 2.49 5 2.35 <5

[0009] The positions, widths and relative intensities of the peaksdepend to a certain extent on the chemical composition of the material(the pattern represented in Table I refers only to materials the networkof which is composed exclusively of silicon oxide, SiO₂or andsynthesized using a quaternary ammonium cation as structure directingagent). Furthermore, the calcination gives rise to significant changesin the X-ray diffraction pattern, due to the elimination of organiccompounds that have been retained in the pores of the zeolite duringsynthesis, so the diffraction pattern of calcinated ITQ-10 of thecomposition SiO₂ is represented. In FIG. 1 there is shown thediffraction pattern of a sample of calcinated ITQ-10 of the compositionSiO₂. TABLE 2 d(Å) I/I_(o)(%) 12.38 70 11.79 90 10.34 30 9.21 20 6.19 154.70 5 4.44 10 3.92 100 3.80 25 3.66 15 3.53 10 3.40 15 3.25 15 3.10 202.94 5 2.84 5 2.63 5 2.48 5 2.35 <5

[0010] From the viewpoint of chemical composition, ITQ-10 ischaracterized by having a (Si+Y)/X ratio higher than 10, wherein theelement x may be constituted exclusively of Al, and due to its lowconcentration of connectivity defects (<15%, preferably <6%).Furthermore, ITQ-10 may be synthesized without Al, or another elementwith oxidation state +3 in which case ITQ-10 is a new polymorphous formof silica of a microporous nature.

[0011] The present invention also refers to the method of preparingITQ-10. This comprises a thermal treatment at a temperature between 80and 200° C., preferably between 130 and 200° C., of a reaction mixturecontaining a source of SiO₂ (as for example tetraethylorthosilicate,colloidal silica, amorphous silica), an organic cation in the form of ahydroxide, preferably 1,4-diquinuclidinium butane dihydroxide (I),hydrofluoric acid and water. Alternatively, it is possible to use theorganic cation in the form of a salt (as for example a halide,preferably chloride or bromide) and to replace the hydrofluoric acid bya fluorine salt, preferably NH₄F. The reaction mixture is characterizedby its relatively low pH, pH<12 preferably <10, whereby it may also beneutral or slightly acid.

[0012] Optionally, it is possible to add a source of another tetravalentY and/or trivadent element X, preferably Ti or Al. The addition of thiselement may be made before heating the reaction mixture or at anintermediate time during said heating. On occasions, it may beconvenient to furthermore introduce, at some stage of the preparation,ITQ-10 crystals (between 0.10 and 15% by weight in respect of the wholeof inorganic acids, preferably between 0.05 and 5% by weight) ascrystallization promoters (seeding). The composition of the reactionmixture corresponds to the general empirical formula

rR(OH)₂:a HF:xX₂O₃:y YO₂:SiO₂:w H₂O

[0013] wherein X is one or several trivalent elements, preferably Al; Yis one or several tetravalent elements; R is an organic cation,preferably 1,4-diquinuclidinium butane; and the values r, a, x, y, and ware within the ranges

[0014] r=R(OH)₂/SiO₂=0.01-1.01 preferably 0.1-1.0

[0015] a=HF/SiO₂=0.01-1.0, preferably 0.1-1.0

[0016] x=X₂O₃/SiO₂=0-0.05

[0017] y=YO₂/SiO₂=0-0.1

[0018] w=H₂O/SiO₂=0-100, preferably 1-50, more preferably 1-15

[0019] The thermal treatment of the reaction mixture may be carried outin a static manner or with agitation of the mixture. Oncecrystallization has ended, the solid product is separated and dried. Thesubsequent calcination at temperatures between 400 and 650° C.,preferably between 450 and 600° C., produces the decomposition of theorganic residues that are occluded within the zeolite, and the exitingthereof and of the fluoride anion whereby the zeolitic channels are leftfree.

[0020] This method of synthesis of the zeolite ITQ-10 has theparticularity that it does not require alkaline cations to be introducedinto the reaction mixture. As a consequence thereof, R is the onlycation that compensates network charges when the zeolite contains atrivalent element within its crystalline network. Thus, a simplecalcination to decompose the organic cation leaves the zeolite in anacid form without the need to resort to processes of cationic exchange.Once calcinated, the material thus responds to the general formula

x(HXO₂):yYO₂:SiO₂

[0021] wherein x has a value lower than 0.1 whereby it may be equal tozero; y has a value lower than 0.1 and may also be equal to zero; X is achemical element with oxidation status +3 and Y is a chemical elementwith oxidation state +4.

EXAMPLES Example 1

[0022] This example illustrates the preparation of 1,4-diquinuclidiniumbutane.

[0023] 17.30 g of 1,4-dibromobutane, 99% Aldrich, and 100 g ethanol aremixed in a 250 ml flasK. Thereafter, 20 g quinuclidine, 97% Aldrich, areadded and stirring is maintained for 3 days. After this time haselapsed, ethanol is eliminated by vacuum concentration in a rotaryevaporator. The resulting solid is washed with ethyl acetate andafterwards with diethyl ester, whereby 36.14 g are obtained with a yieldof 95%. The nuclear magnetic resonance spectrum in D₂O indicates that itis the desired product. i.e. bromide of the organic cation1,4-diquinuclidinium butane. The elemental analysis of the solid is asfollows: 5.93% N, 45.55% C, 8.08% H.

[0024] The hydroxide form of the structure directing agent is obtainedby anionic exchange, whereby Dowex 1 resin (Sigma) that has beenpreviously washed with distilled water up to pH=7. To a solution of 16.3g of the former product in 41.3 g water, 80.5 g resin is added and leftunder stirring for approximately 12 hours. After filtering the resin,the solution is titrated with HCl (aq.) using phenolphthalein asindicator, with an efficiency in the exchange of 92.8%. This solutionmay be concentrated in the rotary evaporator for use thereof in thesynthesis of molecular sieves, for example at a concentration of IN.

Example 2

[0025] This example illustrates the preparation of ITO-10 by means ofthe use of the cation 1,4-diquinuclidinium butane.

[0026] On 68.79 g of a solution of 1,4-diquinuclidinium butane hydroxidecontaining 1,044 hydroxide equivalents in 1000 g, 22.92tetraethylorthosilicate (TEGS) are added. It is left to evaporate untilthe complete elimination of ethanol coming from the hydrolysis of theTEOS plus the quantity of water required so that the final compositionis the indicated one. 2.79 g of HF in water (46.9% by weight) are addedand the mixture is homogenized. The paste obtained is introduced into anautoclave provided with an internal sleeve of polytetrafluoethylene, andheated to 175° C. at the same time that the autoclave is maintainedunder rotation (60 rpm) during 4 days. The autoclave is then cooled, thecontents filtered, the solid washed with water and dried at 100° C.(47.2 g of solid per 100 g gel). The X-ray diffraction pattern showsthat the solid is pure ITQ-10. Calcination at 580° C. in air during 3hours permits elimination of the occluded species.

[0027] The composition of the gel is: SiO₂:0.25 R(OH)₂:0.50 HF; 3.75H₂O.

Example 3

[0028] This example illustrates the preparation of Al-ITQ-10 of a ratioSi/Al=50 using the cation 1,4-diquinuclidinium butane.

[0029] 15.60 g TEOS and 0.31 g aluminium isopropoxide are hydrolized in33.43 g of a 1,4-diquinuclidinium dihydroxide solution wit aconcentration of 1.12 equivalents per 1000 g, an it is left to evaporatein agitation, up to complete elimination of ethanol and part of thewater. When 14.18 g of gel remain 1.42 g HF (46.9% by weight) are addedhomogenizing manually. After subjecting to heating at 175° C. during 11days, Al-ITQ-10 with a ratio Si/Al=53 is obtained with a yield of 26.27g per 100 g gel.

[0030] The composition of the gel is: SiO₂:0.01 Al₂O₃:0.25 R(OH)₂:0.50HF:3.75 H₂O

Example 4

[0031] This example illustrates the preparation of Al-ITQ-10 of a ratioSi/Al 25 using the cation 1,4-diqunuclidinium butane.

[0032] 15.60 g tetraethylorthosilicate (TEOS) and 0.61 g aluminiumisopropoxide are added over 41.60 g of a solution of1,4-diquinuclidinium butane hydroxide containing 0.90 hydroxideequivalents in 1000 g. It is left to evaporate in agitation, up tocomplete elimination of the ethanol coming from the hydrolysis of TEOSplus the quantity of water being necessary for the final composition tobe the indicated one. 1.50 g of a solution of HF in water (49.8% byweight) are added and the mixture is homogenized. The paste obtained isintroduced into an autoclave provided with an inner sleeve ofpolytetraflaoethylene and is heated to 175° C. at the same time theautoclave is maintained under rotation (60 rpm) during 8 days. Theautoclave is then cooled, the contents filtered, the solid washed withwater and dried at 100°. The yield is 2.8 g solid per 100 g gel. TheX-ray diffraction pattern shows that the solid is pure ITQ-10.Calcination at 580° C. in air during 3 hours permits elimination of theoccluded species.

[0033] The composition of the gel is: SiO₂:0.02 Al₂O₃:0.25 R(OH)₂:0.50HF:3.75H₂O.

1. A microporous crystalline material of zeolitic nature with a X-raydiffraction pattern concordant with that established in tables I and IIfor the material as synthesized and after calcination, respectively, andwith a chemical composition in calcinated and anhydrous state which maybe represented by the following empirical formulax(M₁/_(n)XO₂):yYO₂:SiO₂ wherein x has a value lower than 0.1 whereby itmay be equal to zero; y has a value lower than 0.1 and may as well beequal to zero; M is H⁺ or an inorganic cation of a charge +n; X is achemical element with oxidation state +3 (as for example Al, Ga, B, Cr)and Y is a chemical element with oxidation state +4 (as for example Ti,Ge, V).
 2. A zeolite according to claim 1, the chemical composition ofwhich, in calcinated and anhydrous state, may be represented by theempirical formula x(HXO₂):yYO₂:SiO₂ wherein X is a trivalent element(Al, B, Ga, Cr, . . . ), Y is a tetravalent element other than Si (Ti,Ge, V, . . . ), x has a value lower than 0.1 whereby it may be equal tozero; y has a value lower than 0.1 and may also be equal to zero.
 3. Azeolite according to claim 1 the composition of which in calcinated andanhydrous state may be represented as SiO₂.
 4. A method for synthesizingzeolites, wherein a reaction mixture containing a source of SiO₂,1,4-diquinuclidinium butane, a source of fluorine F, a source of one orseveral tetravalent elements Y other than Si, a source of one or severaltrivalent elements X and water, is subjected to heating with or withoutagitation to a temperature between 80 and 200° C., preferably between130 and 200° C. until achieving crystallization, and wherein thereaction mixture has a composition in terms of molar oxide ratios,comprised between the ranges R(OH)₂/SiO₂=0.01-1.0, preferably 0.1-1.0HF/SiO₂=0.01-1.0, preferably 0.1-1.0 X₂O₃/SiO₂=0-0.05 YO₂/SiO₂=0-0.1H₂O/SiO₂=0-100, preferably 1-50, more preferably 1-15.
 5. A method forsynthesizing the zeolite of the previous claims, wherein a reactionmixture containing a source of SiO₂, 1,4-diquinuclidinium butane organiccation, a source of fluoride anions, a source of one or severaltrivalent elements X and water, is subjected to heating with or withoutagitation to a temperature between 80 and 200° C., preferably between130 and 200° C. until achieving crystallization, and wherein thereaction mixture has a composition in terms of molar oxide ratios,comprised between the ranges R(OH)₂/SiO₂=0.01-1.0, preferably 0.1-1.0F/SiO₂=0.01-1.0, preferably 0.1-1.0 X₂O₃/SiO₂=0-0.05 H₂O/SiO₂=0-100,preferably 1-50, more preferably 1-15.
 6. A method for synthesizing thezeolite of claims 1 and 2, wherein a reaction mixture containing asource of SiO₂, 1,4-diquinuclidinium butane organic cation, a source offluoride anions, a source of Al and water, is subjected to heating withor without agitation to a temperature between 80 and 200° C., preferablybetween 130 and 200° C. until achieving crystallization, and wherein thereaction mixture has a composition in terms of molar oxide ratios,comprised between the ranges RF(OH)₂/SiO₂=0.01-1.0, preferably 0.1-1.0F/SiO₂=0-1.0, preferably 0.1-1.0 Al₂O₃/SiO₂=0-0.05 H₂O/SiO₂=0-100,preferably 1-50, more preferably 1-15.
 7. A method for synthesizing thezeolite of claims 1 and 3, wherein a reaction mixture containing asource of SiO₂, 1,4-diquinuclidinium butane organic cation, a source offluoride anions and water, is subjected to heating with our withoutagitation to a temperature between 80 and 200° C., preferably between130 and 200° C. until achieving crystallization, and wherein thereaction mixture has a composition in terms of molar oxide ratios,comprised between the ranges R(OH)₂/SiO₂=0.01-1.0, preferably 0.1-1.0F/SiO₂=0.01-1.0, preferably 0.1-1.0 H₂O/SiO₂=0-100, preferably 1-50,more preferably 1-15.
 8. A method for synthesizing zeolites of claims 1and 2, wherein a reaction mixture containing a source of SiO₂,1,4-diquinuclidinium butane, a source of fluoride anion, a source of oneor several tetravalent elements Y other than Si and water, is subjectedto heating with or without agitation to a temperature between 80 and200° C., preferably between 130 and 200° C. until achievingcrystallization, and wherein the reaction mixture has a composition interms of molar oxide ratios, comprised between the rangesR(OH)₂/SiO₂=0.01-1.0, preferably 0.1-1.0 HF/SiO₂=0.01-1.0, preferably0.1-1.0 YO₂/SiO₂=0-0.1 H₂O/SiO₂=0-100, preferably 1-50, more preferably1-15.
 9. A method of synthesizing a microporous crystalline materialaccording to claims 4-8, of synthesizing the zeolite of claims 1 and 3,wherein the 1,4-diquinuclidinium butane organic cation is added inhydroxide form or in the form of a mixture of hydroxide and anothersalt, preferably a halide and the fluoride anion is added in the form ofhydrofluoric acid or of a salt, preferably ammonium fluoride, in suchmanner that the pH of the mixture is equal to or lower than 12,preferably lower than 11, and it may be even neutral or slightly acid.10. A method of synthesizing a microporous crystalline materialaccording to claim 9 and previous ones, wherein such crystallinematerial has a X-ray diffraction pattern substantially concordant withthat established in tables I and II for the material as synthesized andafter calcination, respectively, and with a chemical composition incalcinated and anhydrous state which may be represented by the followingempirical formula x(M₁/_(n)XO₂):yYO₂:zR:wH₂O wherein x has a value lowerthan 0.1 whereby it may be equal to zero; y has a value lower than 0.1and may as well be equal to zero; M is H⁺ or an inorganic cation of acharge +n; X is a chemical element with oxidation state +3 (as forexample Al, Ga, B, Cr) and Y is a chemical element with oxidation state+4 (as for example Ti, Ge, V).
 11. A method for synthesizing the zeoliteaccording to claims 1-3 and 10 in accordance with the process of claims4-9 and 11, wherein an amount of crystalline material (preferably withthe characteristics of the material of claims 1-4 and 11) is added tothe reaction mixture as crystallization promoter, said amount beingcomprised in the range 0.01 to 15% by weight with respect to the wholeof added silica, preferably 0.05 to 5%.
 12. A method for synthesizingthe zeolite according to claims 1-3 and 10 in accordance with theprocess of claims 4-9, wherein no alkaline cations are added to thereaction mixture.
 13. A method for synthesizing the zeolite according toclaims 1, 2 and 10 in accordance with the process of claims 4, 5, 6, 8,9 and 11, wherein a source of a tetravalent element other than Si, or ofa trivalent element, is added during an intermediate step during heatingof the reaction mixture.